This loop relies on a brilliant feedback loop between Boros Reckoner and the transformed side of Ill-Tempered Loner // Howlpack Avenger, both of which possess damage-redirection triggers that care whenever a permanent you control is dealt damage. By initially pinging Boros Reckoner, you kick off an automatic chain reaction where it redirects damage to Howlpack Avenger, which in turn fires damage right back at Boros Reckoner. Because neither creature dies from this exchange, their respective reflexive damage triggers continuously feed into one another to deal infinite damage to any target you choose.